Composite plate for stair treads and the like



`March l6,`1937.-` y J. SC'HMLLERQSR 2,073,758 coMfosITE PLATE FOR STAIR TREADS AND THE LIKE 'Filed July :51, 1955 F26. a. y [1575' 0 2/ 20 Q M/ f7 A n la hf A45 n f wise throughy thesurface of'theA body portion of' `a. plate and'provlde spaced points at'which such insert will project to form a non-slipping surn ,i `Patented Mar.E 16,5193? n Pari:Nrl OFFICE g ooMPosrfriirLATE ironv strain 4 `'rHIiLrKF 6. Claims.

This invention b `as indicated" relates to a coml posite plate useful for a wide variety of purposes. y including stair treads, floor plates, street and sidewalk 'plates and covers", and like usas.` More particu1arly`,` it comprisesa plate made ofrelativelyA soft# metal engaged about a flexible` reinforcing wear-,resisting element formed o'frelatively @harder metahl the present invention it is pre- 4 ferred tbfuse aluminum or aluminum `alloy as `When aluminum or` aluminum alloyor some l5 similarrnetaljof high crystallization shrinkage land high heat conductivity 4is',` used as thebmain 'body portion of theplate, if an inserted wear ele- "ment isused which wouldnotcompensate for the high shrinkager and expansion characterisg `tics of the metal, a `satisfactoryfinished productV freehof cracksandj warpage could not be provided.

` 5 With the use"`of "expanded metal, howevenelas-N ticityl in all directions is provided for, and thev full andfreeshrinkage and expansion of they y25 body portion of the plate maytake place without interfering with" thefrm engagement of the aluminum withthefreinforcingandwear-resist- "inginsertfv The insert' is designed not to `strengthen p50' the pierces such,` paraiso' to provide @tread i surface which will be maintained asa non-slip-V y pingtread surface evenfthoughfsubjected to f b The Vprincipal4 object `of the present invention '35 is toprovi'de an improved wear plate wherein meti alhaving high thermalconductivity and a large factor of crystallization shrinkage `,may be uti- "lized as a tread plate*having-a` non-slipping `in-f` sert whereby a satisfactory surface will `be continuously maintained throughout a long period f 'ofuse. H wear plate wherein an'inner reinforcing and larly disposed-portions adapted to project edgesimple methodof forming a tread plate which will bottom? faces of thetread plate; b wear-resisting member is provided'having angu Anotherobiectofthe invention is to provide a Johnfscnmuer, sf., nakewonalohi i Applicata@ Juiy s1, 1935, sel-iai Nq.' 34,064

embedded in a body;` portion of :metal of a lesser `degree of` hardness` b, 1 Y Another objectfof the invention isxto provide a lwear plate wherein the non-slipping elements are formed in edgewise angular position and em- `bedded in the main body portionof the plateand are of such extent that they will wear down to approximately the same degree as the main body portionc-f the plate so that a non-slipping` surface willybejmaintained'and one having a satisfactory appearance because of Vthe approximately uniform wear on the several elements thereof, `(Zither and further. objects of the invention will appear in the, course ofjthe followingdescription. '4 n To the accomplis nient of the foregoing and relatedV ends, 'said invention,V then, consists of `the product 'Y and method hereinafter fully described and particularly pointed out in the claims. "I'he annexed drawing and thefollowing description set forthin" detail certainmeans `and `modesl of carrying' out the invention, and prodl" ucts resulting `therefrom, such disclosed means, `modes and products, illustrating however, but

several ofbvarious applications of the principle of the invention: Y A

,In said annexedffdrawingz" i n' i i Figurel isatop-plan view illustrating a tread plate `embedyingthe principles of the invention; Figure2 is aside elevation of the lstructure shown in FigureV 1; n

partly jbroken away, showing the structure illustrated in Figures l and 2; i

Figure 4` is astill further enlarged View of the structure shownK in Figures 1 to 3; l n Figure 5 is` an enlarged fragmentary sectional view ofthe structure shown in Figures 3 and 4, taken along the line 5 5, shown in Figure 4;

" Figure 6 is anf'enlarged fragmentary sectional i u i n b f view of a modified form of construction wherein `Another object ofthe invention isto provide a the embedded'sheetV projects from the top and f Figure'l is an enlarged fragmentary sectional view showing a treadfplate having two embedded sheets of expanded metal, one projecting through the top and the other throughlthe bottom surface;`andv Figure 8 is a diagrammatic view, partly in section, illustrating the `method of molding the tread plate. i f Y Asis clearly shown in the drawing, theplate I comprises `a main body portion 2 preferably of aluminum or aluminum alloy, and a grid portion 3 preferably formed of expanded metal produced Figure 3 is an enlarged fragmentary plan view,

by slitting sheet steel and drawing the same. Through the use of an embedded sheet of expanded metal or similar steel grid, preferably deformable in all directions, a plate may be produced having a capacity to expand or contract without fracturing, and at the same time bring about the combination of effects which resides in the use of an aluminum plate with a steel insert to form a non-slipping surface and produce an l0 article which will be of good appearance throughout its entire period of use even though subjected to very severe usage.

The sheet of expanded metal may be of the full size of the plate or may stop short of the margins thereof so as to provide a central area having the roughened non-slipping surface. 'Ihe preferred form of structure would carry the area of non-slipping surface substantially over the entire extent of the plate, particularly where the structure was incorporated in a stair tread.

Through the use of expanded metal, as is clearly shown in Figure 5, two series of angularly disposed parallel wearing portions 4, 5 are provided, such portions being in different rows transversely and ilongitudinally, respectively. 'I'he intermediate portions of the expanded metal connect the parallel wearing portions to each other and yield whenever pressure is placed upon the structure. In the form shown in Figure i5, the expanded metal grid is positioned so as to project slightly from the upper surface of the tread plate and has a relatively large body 6 of aluminum beneath the same. 4 Y

In the form of construction shown in Figure 6, the grid 'I is of such size relatively to the body 8 of the tread plate as to have its wearing portions project from each side of the plate.

In Figure 7, two expanded metal grids 9, I0 are used, one adjacent the top surface and one adjacent the bottom surface of the plate I I, such grids being held in spaced relation by means of chaplets I2 during the process of forming the same.

The tread plate may be made in various ways .45 and is preferably cast about the expanded metal or similar form of grid. It may be cast in sand molds, permanent molds, semi-permanent molds, or may be otherwise fabricated.

'I'he preferred method of making the wear plate is in a sand mold and is illustrated in Figure 8, and preferably comprises a flask I3 having a cope portion I4 and drag portion I5` providing a molding cavity I6, the size of the plate to be formed, in the drag portion I5, and having a flat face I'I in the cope portion Il of the mold, as well as a sprue passageway I8 communicating with peripheral runners I9 and entering the margins of the casting cavity for the plate through a series of thin gates 20 preferably equally spaced from each other which are readily frangible when the plate has been formed, and thus the auxiliary metal may be broken free of the plate without machining operations. 'I'he casting cavity may be formed either in the drag or the cope, but is rpreferably formed in the drag. The gates and peripheral runner are formed at the parting line, but may-be formed in either thecopeor drag, or partly irnreach. i vhas been stated, the inserted web or grid I 1.0" may be of less than the full extent of the plate to be cast and may be held in position prelimiynary to the pouring of the metal by means of a number of chaplets 2| placed above the grid. Thus after the plate is formed the grid will be 75 held against the bottom of the drag to form the top of the plate through the action of the chaplets, and the body of the plate may have at its base an area of metal free of the inserted grid.

For certain uses the grid may be made of sutilcient thickness so as to have the metal thereof extend completely through the body portion of the plate 'as shown in Figure 6, and thus a nonslipping surface would be provided no matter to what extent the article would be subjected to Wear. It may also be formed as shown in Figure 7 where a separate grid is provided adjacent both the top and bottomA surfaces of the tread plate.

For certain uses, however, it may be desirable to have a body of aluminum or other metal free of inserted metal completely around the marginal portions of the device, as Well as forming a base pad free of inserted metal. In general, however, the amount of space free of the non-slipping grid will be kept at a minimum for the reason that the marginal areas of such plates might themselves present a hazard, particularly when used as a, stair tread and subjected to the polishing action of severe use.

Other modes of applying the principle of my invention may be employed instead of those explained, change being made as regards the means and the steps herein disclosed and the forms Lof the product resulting therefrom, provided those stated by any one of the following claims or their equivalents be employed or embodied therein.

I therefore particularly point out and distinctly claim as myinvention:

1. An article of the character described hav-- ing in combination a flat elongated body member of relatively soft material, and a reinforcing grid embedded intermediate the top and bottom surfaces thereof, said grid having angular connecting elements providingan open mesh structure with the openings in staggered relation to each other in adjacent rows whereby said grid is freely ex: pansible and contractible, and portions of vsaic grid projecting froml the upper surface of said body member to provide parallel series of spaced ribs to serve as wear-resisting elements.

2. An article of the character ,described having in combination a flat elongated body formed of metal of high crystallization shrinkage and high heat transfer characteristics, having embedded therein, and partially projecting from the upper surface of said body, a wear-resisting grid of relatively harder metal and provided with staggered inclined ribs and angular connecting elements and freely expansible or contractible. 3. An article lof the character described having in combination a flat elongated body formed of metal of high crystallization shrinkage and high heat transfer characteristics, having embedded therein a wear-resisting grid of relatively harder metal and rfreely expansible or contractible, said inserted metal vbeing formed of slitted and expanded sheet metal and having a series of angularly disposed webs throughout the structure, the upper edges of said websprojecting above the upper surface of said body.

4. An article of the character described having in combination-a fiat elongated body formed of metal of high crystallization shrinkage and high heat transfer characteristics, having embedded therein a wear-resisting grid of relatively harder metal and freely expansible or contractible, said inserted metal being formed of slitted and expanded sheet metal and having a plurality of f series of angularly disposed webs throughout the structure, said respective series being in staggered relation to each other and the upper edges of said webs projecting above the upper surface of said `body.

5. An article of the character described having in combination a iat elongated b member formed of metal of high crystalliza' von shrinkage and high heat transfer characteristics, having n embedded intermediate the top and bottom surfaces thereof a wear-resisting grid of 'relatively harder metal and freely expansible or contractible, said grid beingformed of slitted and expandedsheet metal and having a series of angularly disposed webs throughout the structure, the edges of said webs projecting outwardly from each of the top and bottom surfaces in alternate ribs of roughly crescent shape.

6. An article of the character described having in combination a at elongated body member formed of metal of; high crystallization shrinkage and high heat transfer characteristics, having embedded adjacent each of the top and bottom surfaces thereof a wear-resisting grid of relatively harder metal and freely expansible or contractible, said inserted metal being formed of slitted and expanded sheet metal and having a series of angularly disposed webs throughout the structure, the outer edges of said respective grids projecting above the respective top and bottom surfaces of said body in alternately spaced ribs of roughly crescent shape.

JOHN SCHMEILER. SR. 

